Position accuracy of industrial robots is one of the most concerned issues for manufacturers and users. The methods of measuring and analyzing the performance indexes of industrial robots accurately, simply and reliably are important for evaluating the performance of industrial robots. In this paper, a set of industrial robot performance test system is developed based on the Qt (graphics application development framework) with laser trackers as the measuring device. Then, the high effectiveness of the proposed performance test system of industrial robots is verified by testing industrial robots. For the data processing of the trajectory, the processing of redundant data is very important, which has a direct impact on the accuracy of the test results. Therefore, algorithms of filtering are need to improve the stability of test system. Experimental results reveal the high reliability of the performance test system of industrial robots by comparison with commercial system.
The Articulated Arm Coordinate Measuring Machine (AACMM) is a kind of coordinate measuring devices in the form of an articulated robot. To improve the accuracy of AACMM, a kinematic identification method is presented in this paper. Firstly, we perform the kinematics modeling and simulation to realize the kinematic transformation from the joint space to the coordinate space. Then, we establish an error model and use least squares method to identify kinematic parameters. And the effectiveness of the least squares method for kinematic parameter identification is studied. Finally, the experiments of single point repeatability accuracy and the standard gauge accuracy are performed. The experimental results show that proposed the kinematic identification method can effectively improve the measurement accuracy of the joint coordinate measuring machine.
The articulated arm coordinate measuring machine (AACMM) is a new type of non-orthogonal coordinate measuring machine (CMM). Unlike the traditional orthogonal CMM which has three linear guides the AACMM is composed of a series of linkages connected by rotating joints. Firstly, the coordinate systems of the AACMM are established according to D-H method, the homogeneous transformation matrixes from the probe to the base of the AACMM are derived. And the graphic simulation system of the AACMM is built in Matlab, which verify the magnitude and direction of the joint angles qualitatively. Then, the data acquisition software of the AACMM is compiled by Visual C++, and there is a statistical analysis on the calculated measuring coordinates and actual coordinates, which indicates that the kinematic model of the AACMM is correct. The kinematic model provides a basis for measurement, calibration and error compensation of the AACMM.
Proc. SPIE. 9446, Ninth International Symposium on Precision Engineering Measurement and Instrumentation
KEYWORDS: Data acquisition, Sensors, Field programmable gate arrays, Telecommunications, Diffraction gratings, Voltage controlled current source, Clocks, Signal processing, Virtual colonoscopy, Computing systems
A novel cylindrical capacitive sensor (CCS) with differential, symmetrical and integrated structure was proposed to measure multi-degree-of-freedom rotation errors of high precision spindle simultaneously and to reduce impacts of multiple-sensors installation errors on the measurement accuracy. The nonlinear relationship between the output capacitance of CCS and the radial gap was derived using the capacitance formula and was quantitatively analyzed. It was found through analysis that the thickness of curved electrode plates led to the existence of fringe effect. The influence of the fringe effect on the output capacitance was investigated through FEM simulation. It was found through analysis and simulation that the CCS could be optimized to improve the measurement accuracy.
The Articulated Arm Coordinate Measuring Machine (AACMM) is a new type of non-orthogonal system precision instrument with the advantages of large measuring range, small volume, low weight and portability. The kinematic models of AACMM are commonly established with the Denavit-Hartenberg (D-H) method. However, the D-H model exhibits the singularity in consecutive parallel joint axes due to it is neither complete nor parametrically continuous. The kinematic model of the AACMM established with MCPC (modified complete and parametrically continuous) method overcomes the disadvantages of incomplete and parametrically discontinuous of the D-H method. The transformation matrixes are obtained based on the MCPC method, which realizes the mapping form the joint space to measuring space of the AACMM. Numerical calculation and graphic simulation are used to verify the kinematic model of the AACMM. The result shows that the kinematic model is correct. The kinematic model of the AACMM based on MCPC method can provide a theoretical basis for measurement and calibration, and it also introduces a new kinematic modeling approach for the AACMM.